After sacrificing everything to help the Flash put the universe back together and save Bruce Wayne's life, Thomas Wayne wakes up in a world he thought was no more. Forced to don the cowl once again, Batman prowls the streets of Gotham searching for answers to how this world still exists, but what he starts to uncover will send him hurtling around the globe. The hunt for the Clockwork Killer brings Batman to Europe and face to face with the mad king, Aquaman. On the eve of Aquaman's sinking of London, Batman infiltrates his stronghold and goes on the warpath for answers. Nothing matters to Batman, whose world is already dead, but if he can track down the Clockwork Killer, Thomas can save his son's world and put everything back together again.